US20210036409A1 - Wireless communication module - Google Patents
Wireless communication module Download PDFInfo
- Publication number
- US20210036409A1 US20210036409A1 US17/072,667 US202017072667A US2021036409A1 US 20210036409 A1 US20210036409 A1 US 20210036409A1 US 202017072667 A US202017072667 A US 202017072667A US 2021036409 A1 US2021036409 A1 US 2021036409A1
- Authority
- US
- United States
- Prior art keywords
- current path
- frequency filter
- wireless communication
- switching element
- communication module
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
- H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
- H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
- H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
- H01Q1/243—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with built-in antennas
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
- H01Q5/30—Arrangements for providing operation on different wavebands
- H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
- H01Q5/342—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes
- H01Q5/357—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes using a single feed point
- H01Q5/364—Creating multiple current paths
- H01Q5/371—Branching current paths
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
- H01Q9/0421—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with a shorting wall or a shorting pin at one end of the element
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
- H01Q9/42—Resonant antennas with feed to end of elongated active element, e.g. unipole with folded element, the folded parts being spaced apart a small fraction of the operating wavelength
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
- H02M1/4225—Arrangements for improving power factor of AC input using a non-isolated boost converter
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/075—Ladder networks, e.g. electric wave filters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
- H02M1/007—Plural converter units in cascade
-
- H02M2001/007—
Definitions
- the present disclosure relates to a wireless communication module.
- Japanese Unexamined Patent Application Publication No. 2004-187446 indicated below discloses a DC-DC converter that supplies direct current (DC) power to a power amplifier used in a transmit circuit for wireless communication.
- a band-stop filter corresponding to a frequency range of the difference between the transmit frequency band and the receive frequency band is provided at the output section of the DC-DC converter. By providing the band-stop filter, the influence of noise on the reception frequency band due to the transmission power of the transmit circuit is suppressed.
- a method is used in which a smoothing capacitor of a capacitance of several tens of ⁇ F or higher is coupled to the output section of a DC-DC converter to reduce noise over a wide frequency range.
- noise components leaking from the output section of the DC-DC converter to the outside are caused to flow to the ground, and as a result, noise can be reduced.
- the method of causing noise components to flow to the ground does not necessarily achieve a sufficient noise reduction effect.
- Ringing noise caused by switching of the DC-DC converter appears in the frequency band up to the several GHz band.
- the noise in the several GHz band flows into the ground through the stray capacitance of the substrate, the smoothing capacitor, and the like.
- an inverted F antenna or a planar inverted F antenna that is suitable for downsizing and that can improve radiation efficiency is often used for wireless earphones, IoT devices, and the like.
- the inverted F antenna or the planar inverted F antenna is coupled to the ground.
- a low-power wide-area (LPWA) communication system typified by WiFi or a personal area network (PAN) typified by Bluetooth (registered trademark) is used by wireless earphones and IoT devices.
- the printed boards of these devices are smaller than the printed boards of smart phones and the like, and thus, it is difficult to secure a sufficiently large ground. Furthermore, the distance between the noise source and the antenna for wireless communication is short. As described above, when it is difficult to secure a sufficiently large ground, the noise flowing into the ground greatly affects the antenna.
- the present disclosure provides a wireless communication module that suppresses deterioration of wireless communication quality due to noise generated in a DC-DC converter.
- a wireless communication module having a DC-DC converter including a switching element coupled in a current path between an input terminal and an output terminal and including a smoothing capacitor coupled between the output terminal and a ground, a bypass capacitor coupled between the input terminal and the ground, an antenna element sharing the ground with the DC-DC converter, and a frequency filter inserted in series in at least either a current path between the switching element and the smoothing capacitor or a current path between the bypass capacitor and the switching element and having a stop band that is an operating frequency band of the antenna element.
- the frequency filter reduces the noise flowing into the ground through the smoothing capacitor or the bypass capacitor, and thus, it is possible to reduce the noise transferred to the antenna via the ground.
- FIG. 1 is an equivalent circuit diagram of a wireless communication module according to a first embodiment
- FIGS. 2A and 2B are equivalent circuit diagrams illustrating examples of a frequency filter
- FIG. 3 is a graph illustrating the transmission characteristic S 21 of each of an inductor and a ferrite bead used in an evaluation experiment
- FIG. 4 is a graph illustrating a result obtained by measuring spectrums of noise coupled to an antenna element with the use of a spectrum analyzer connected through a coaxial cable in the evaluation experiment;
- FIG. 5 is a bar graph illustrating noise levels at frequencies of 2444 MHz, 2446 MHz, and 2448 MHz extracted from the noise level spectrums illustrated in FIG. 4 ;
- FIG. 6 is an equivalent circuit diagram of a wireless communication module according to a second embodiment
- FIG. 7 is an equivalent circuit diagram of a wireless communication module according to a third embodiment.
- FIGS. 8A and 8B are equivalent circuit diagrams of wireless communication modules according to a fourth embodiment and a modified example.
- a wireless communication module according to a first embodiment will be described with reference to FIGS. 1 to 5 .
- FIG. 1 is an equivalent circuit diagram of a wireless communication module 10 according to the first embodiment.
- the wireless communication module 10 according to the first embodiment includes a power supply circuit 20 using a DC-DC converter, a frequency filter 30 , a bypass capacitor 40 , a transceiver circuit 41 , and an antenna element 50 .
- the power supply circuit 20 includes an input terminal 21 , an output terminal 22 , and a ground 27 .
- the bypass capacitor 40 is coupled between the input terminal 21 and the ground 27 .
- a DC power supply 60 is coupled between the input terminal 21 and the ground.
- the DC voltage outputted from the output terminal 22 of the power supply circuit 20 is applied to the transceiver circuit 41 .
- the transceiver circuit 41 transmits a high frequency signal to the antenna element 50 .
- the antenna element 50 is, for example, an inverted F antenna or a planar inverted F antenna and a feed point of the antenna element 50 is coupled to the transceiver circuit 41 (the IC and part of peripheral components).
- the antenna element 50 shares the ground with the power supply circuit 20 .
- a short line 52 of the antenna element 50 is coupled to the same ground as the ground 27 of the power supply circuit 20 .
- the transceiver circuit 41 includes, for example, a baseband circuit, a modulation/demodulation circuit, a band pass filter, a diplexer, a power amplifier, a low-noise amplifier, and the like.
- the power supply circuit 20 mainly has two current paths A 1 and A 2 .
- the current path A 1 starts from the input terminal 21 and reaches the output terminal 22 via a switching element 23 and an output inductor 25 .
- the other current path A 2 starts from the ground 27 and reaches the output terminal 22 via another switching element 24 and the output inductor 25 .
- a smoothing capacitor 26 is coupled between the output terminal 22 and the ground 27 .
- a diode in which the forward direction is a direction from the ground 27 to the output inductor 25 may be used.
- the DC-DC converter including the switching elements 23 and 24 is a DC-DC buck converter.
- the frequency filter 30 is coupled in series to the current path on the switching element 23 side with respect to the connection point of the smoothing capacitor 26 .
- the frequency filter 30 is a band-stop filter in which the operating frequency band of the antenna element 50 is a stop band.
- FIG. 1 illustrates an example in which the frequency filter 30 is inserted in the current path A 1 between the switching element 23 and the output inductor 25 .
- FIG. 2A is an equivalent circuit diagram illustrating an example of the frequency filter 30 .
- a ferrite bead (F.B.) can be used as the frequency filter 30 .
- FIG. 2B is an equivalent circuit diagram illustrating another example of the frequency filter 30 .
- An LC parallel resonant circuit can be used as the frequency filter 30 .
- the LC parallel resonant circuit reflects a part of the signal in the frequency range near the resonant frequency.
- the ferrite bead attenuates the signal of a frequency in the stop band by converting the signal into heat. In the case in which the influence of the reflected wave cannot be ignored, it is preferable to use a ferrite bead as the frequency filter 30 .
- the ringing noise caused due to switching of the switching elements 23 and 24 is attenuated or reflected by the frequency filter 30 , and as a result, it is possible to reduce the noise flowing into the ground 27 through the smoothing capacitor 26 . Accordingly, it is possible to suppress deterioration of quality of communication using the antenna element 50 .
- the stop band of the frequency filter 30 can be set to the operating frequency band of the antenna element 50 . When the antenna element 50 operates in the 2.4 GHz band, the stop band of the frequency filter 30 may be set to the 2.4 GHz band; when the antenna element 50 operates in the 5 GHz band, the stop band of the frequency filter 30 may be set to the 5 GHz band.
- the noise coupled to the antenna element 50 during WiFi search is measured in the state in which the transceiver circuit 41 ( FIG. 1 ) is disconnected from a feed point 51 ( FIG. 1 ) of the antenna element 50 and the power supply circuit 20 operates in a shield box.
- the evaluation experiment was conducted with respect to three kinds of configurations: a configuration in which the frequency filter 30 is not inserted, a configuration in which a 15 nH inductor is used as the frequency filter 30 , and a configuration in which a ferrite bead is used as the frequency filter 30 .
- the antenna element 50 used was one that operates in the 2.4 GHz band.
- FIG. 3 is a graph illustrating the transmission characteristic S 21 of each of the inductor and the ferrite bead used in the evaluation experiment.
- the horizontal axis represents the frequency in the unit of “MHz” and the vertical axis represents the transmission characteristic S 21 in the unit of “dB”.
- the transmission characteristic S 21 indicated in FIG. 3 is measured by using a measurement system of a 50 n characteristic impedance.
- the solid line and the dashed line in the graph of FIG. 3 respectively indicate the transmission characteristics S 21 of the ferrite bead and the inductor.
- As the inductor one with a resonance point at 6 GHz, which is determined in accordance with inductance and stray capacitance, was used.
- As the ferrite bead one with the 2.4 GHz stop band was used.
- FIG. 4 is a graph illustrating spectrums of noise coupled to the antenna element 50 ( FIG. 1 ).
- the horizontal axis represents the frequency in the unit of “MHz” and the vertical axis represents the noise level in the unit of “dBm”.
- the square symbols in the graph of FIG. 4 indicate noise levels in the case in which the frequency filter 30 ( FIG. 1 ) is not inserted.
- the triangle symbol and the dashed line indicate noise levels in the case in which an inductor is used as the frequency filter 30 .
- the circle symbols and the solid line indicate noise levels in the case in which a ferrite bead is used as the frequency filter 30 .
- the high noise level appearing near the frequency of 2455 MHz is caused by signals for WiFi search.
- the thin solid line illustrated in the graph of FIG. 4 indicates the noise floor.
- FIG. 5 is a bar graph illustrating noise levels at frequencies of 2444 MHz, 2446 MHz, and 2448 MHz extracted from the noise level spectrums illustrated in FIG. 4 .
- the vertical axis in FIG. 5 represents the noise level relative to the noise floor.
- the noise level is lower than that in the case in which the frequency filter 30 is not inserted and in the case in which an inductor is used as the frequency filter 30 .
- the wireless communication module 10 according to a second embodiment will be described with reference to FIG. 6 .
- description of the configuration common to the wireless communication module according to the first embodiment will be omitted.
- FIG. 6 is an equivalent circuit diagram of the wireless communication module 10 according to the second embodiment.
- the frequency filter 30 is inserted in the current path on the output side with respect to the switching element 23 ; and on the input side, the switching element 23 is directly coupled to the bypass capacitor 40 .
- a frequency filter 31 on the input side is coupled in series between the bypass capacitor 40 and the switching element 23 (between the bypass capacitor 40 and the input terminal 21 ).
- the frequency filter 31 on the input side has the same filter characteristic as that of the frequency filter 30 on the output side.
- the frequency filter 31 is inserted also on the input terminal 21 side, and as a result, it is possible to inhibit the propagation of noise generated on the input terminal 21 side and transferred to the antenna element 50 via the bypass capacitor 40 and the ground 27 .
- the frequency filter 30 is inserted on the output side with respect to the switching element 23 and the other frequency filter 31 is inserted on the input side.
- the frequency filter 30 on the output side is removed and the frequency filter 31 is coupled only on the input side.
- a frequency filter may be inserted in series in at least either the current path between the switching element 23 and the smoothing capacitor 26 or the current path between the switching element 23 and the bypass capacitor 40 .
- the wireless communication module 10 according to a third embodiment will be described with reference to FIG. 7 .
- description of the configuration common to the wireless communication module ( FIG. 6 ) according to the second embodiment will be omitted.
- FIG. 7 is an equivalent circuit diagram of the wireless communication module 10 according to the third embodiment.
- the wireless communication module 10 according to the second embodiment has the one antenna element 50 .
- the wireless communication module 10 according to the third embodiment includes, in addition to the antenna element 50 , an antenna element 55 that operates in another frequency band.
- the one antenna element 50 operates in the 2.4 GHz band and the other antenna element 55 operates in the 5 GHz band.
- the transceiver circuit 41 transmits and receives signals in two frequency bands.
- the transceiver circuit 41 includes a baseband circuit and a high frequency circuit (RF circuit), in which the baseband circuit and the high frequency circuit are both coupled to a duplexer (separator).
- another frequency filter 32 is coupled in series in the current path between the switching element 23 and the smoothing capacitor 26 .
- the stop bands of the frequency filters 30 and 32 are the respective operating frequency bands of the antenna elements 50 and 55 .
- another frequency filter 33 is coupled in series in the current path between the switching element 23 and the bypass capacitor 40 .
- the stop bands of the frequency filters 31 and 33 are the respective operating frequency bands of the antenna elements 50 and 55 .
- the wireless communication module 10 according to the third embodiment can perform wireless communication in two frequency bands. Furthermore, in the two frequency bands, it is possible to reduce the noise flowing into the antenna elements 50 and 55 through the ground 27 .
- FIGS. 8A and 8B a wireless communication module according to a fourth embodiment will be described with reference to FIGS. 8A and 8B .
- description of the configuration common to the wireless communication module ( FIG. 1 ) according to the first embodiment will be omitted.
- FIG. 8A is an equivalent circuit diagram of the wireless communication module 10 according to the fourth embodiment.
- a switching circuit 71 forming a part of the power supply circuit 20 ( FIG. 1 ) and a WiFi module 70 including the transceiver circuit 41 are used.
- the power supply circuit 20 includes the switching circuit 71 included in the WiFi module 70 , the external output inductor 25 , and the smoothing capacitor 26 .
- the frequency filter 30 is coupled in series between the switching circuit 71 and the output inductor 25 .
- An external power supply terminal of the WiFi module 70 serves as the input terminal 21 of the power supply circuit 20 .
- the bypass capacitor 40 is coupled between the input terminal 21 and the ground 27 .
- the DC voltage outputted from the output terminal 22 of the power supply circuit 20 is inputted to the WiFi module 70 .
- FIG. 8B is an equivalent circuit diagram of the wireless communication module 10 according to a modified example of the fourth embodiment.
- the WiFi module 70 not including the power supply circuit 20 is used.
- the switching circuit 71 , the output inductor 25 , and the smoothing capacitor 26 of the power supply circuit 20 are externally coupled outside the WiFi module 70 .
- the DC voltage applied to the external power supply terminal of the WiFi module 70 is applied to the input terminal 21 of the external power supply circuit 20 .
- the frequency filter 30 is coupled in series between the switching circuit 71 and the output inductor 25 .
- the frequency filter 30 can be externally coupled to the WiFi module 70 together with the output inductor 25 and the smoothing capacitor 26 .
- the frequency filter 30 By externally coupling the frequency filter 30 , it is possible to suppress deterioration of wireless communication quality due to the noise flowing into the ground 27 , similarly to the case of the first embodiment.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transceivers (AREA)
- Dc-Dc Converters (AREA)
- Filters And Equalizers (AREA)
- Noise Elimination (AREA)
Abstract
Description
- This application claims benefit of priority to International Patent Application No. PCT/JP2019/015150, filed Apr. 5, 2019, and to Japanese Patent Application No. 2018-084784, filed Apr. 26, 2018, the entire contents of each are incorporated herein by reference.
- The present disclosure relates to a wireless communication module.
- Japanese Unexamined Patent Application Publication No. 2004-187446 indicated below discloses a DC-DC converter that supplies direct current (DC) power to a power amplifier used in a transmit circuit for wireless communication. A band-stop filter corresponding to a frequency range of the difference between the transmit frequency band and the receive frequency band is provided at the output section of the DC-DC converter. By providing the band-stop filter, the influence of noise on the reception frequency band due to the transmission power of the transmit circuit is suppressed.
- Usually, a method is used in which a smoothing capacitor of a capacitance of several tens of μF or higher is coupled to the output section of a DC-DC converter to reduce noise over a wide frequency range. When this method is used, noise components leaking from the output section of the DC-DC converter to the outside are caused to flow to the ground, and as a result, noise can be reduced. However, according to the study conducted by the inventors of the present application, it has been found that the method of causing noise components to flow to the ground does not necessarily achieve a sufficient noise reduction effect.
- Ringing noise caused by switching of the DC-DC converter appears in the frequency band up to the several GHz band. The noise in the several GHz band flows into the ground through the stray capacitance of the substrate, the smoothing capacitor, and the like. In addition, an inverted F antenna or a planar inverted F antenna that is suitable for downsizing and that can improve radiation efficiency is often used for wireless earphones, IoT devices, and the like. The inverted F antenna or the planar inverted F antenna is coupled to the ground. When the noise caused in the DC-DC converter is transferred directly to the antenna via the ground, the quality of wireless communication is degraded.
- A low-power wide-area (LPWA) communication system typified by WiFi or a personal area network (PAN) typified by Bluetooth (registered trademark) is used by wireless earphones and IoT devices. The printed boards of these devices are smaller than the printed boards of smart phones and the like, and thus, it is difficult to secure a sufficiently large ground. Furthermore, the distance between the noise source and the antenna for wireless communication is short. As described above, when it is difficult to secure a sufficiently large ground, the noise flowing into the ground greatly affects the antenna.
- Accordingly, the present disclosure provides a wireless communication module that suppresses deterioration of wireless communication quality due to noise generated in a DC-DC converter.
- According to an aspect of the present disclosure, provided is a wireless communication module having a DC-DC converter including a switching element coupled in a current path between an input terminal and an output terminal and including a smoothing capacitor coupled between the output terminal and a ground, a bypass capacitor coupled between the input terminal and the ground, an antenna element sharing the ground with the DC-DC converter, and a frequency filter inserted in series in at least either a current path between the switching element and the smoothing capacitor or a current path between the bypass capacitor and the switching element and having a stop band that is an operating frequency band of the antenna element.
- The frequency filter reduces the noise flowing into the ground through the smoothing capacitor or the bypass capacitor, and thus, it is possible to reduce the noise transferred to the antenna via the ground.
-
FIG. 1 is an equivalent circuit diagram of a wireless communication module according to a first embodiment; -
FIGS. 2A and 2B are equivalent circuit diagrams illustrating examples of a frequency filter; -
FIG. 3 is a graph illustrating the transmission characteristic S21 of each of an inductor and a ferrite bead used in an evaluation experiment; -
FIG. 4 is a graph illustrating a result obtained by measuring spectrums of noise coupled to an antenna element with the use of a spectrum analyzer connected through a coaxial cable in the evaluation experiment; -
FIG. 5 is a bar graph illustrating noise levels at frequencies of 2444 MHz, 2446 MHz, and 2448 MHz extracted from the noise level spectrums illustrated inFIG. 4 ; -
FIG. 6 is an equivalent circuit diagram of a wireless communication module according to a second embodiment; -
FIG. 7 is an equivalent circuit diagram of a wireless communication module according to a third embodiment; and -
FIGS. 8A and 8B are equivalent circuit diagrams of wireless communication modules according to a fourth embodiment and a modified example. - A wireless communication module according to a first embodiment will be described with reference to
FIGS. 1 to 5 . -
FIG. 1 is an equivalent circuit diagram of awireless communication module 10 according to the first embodiment. Thewireless communication module 10 according to the first embodiment includes apower supply circuit 20 using a DC-DC converter, afrequency filter 30, abypass capacitor 40, atransceiver circuit 41, and anantenna element 50. Thepower supply circuit 20 includes aninput terminal 21, anoutput terminal 22, and aground 27. Thebypass capacitor 40 is coupled between theinput terminal 21 and theground 27. ADC power supply 60 is coupled between theinput terminal 21 and the ground. - The DC voltage outputted from the
output terminal 22 of thepower supply circuit 20 is applied to thetransceiver circuit 41. Thetransceiver circuit 41 transmits a high frequency signal to theantenna element 50. Theantenna element 50 is, for example, an inverted F antenna or a planar inverted F antenna and a feed point of theantenna element 50 is coupled to the transceiver circuit 41 (the IC and part of peripheral components). Theantenna element 50 shares the ground with thepower supply circuit 20. For example, ashort line 52 of theantenna element 50 is coupled to the same ground as theground 27 of thepower supply circuit 20. - The
transceiver circuit 41 includes, for example, a baseband circuit, a modulation/demodulation circuit, a band pass filter, a diplexer, a power amplifier, a low-noise amplifier, and the like. - Next, the configuration of the
power supply circuit 20 will be described. Thepower supply circuit 20 mainly has two current paths A1 and A2. The current path A1 starts from theinput terminal 21 and reaches theoutput terminal 22 via aswitching element 23 and anoutput inductor 25. The other current path A2 starts from theground 27 and reaches theoutput terminal 22 via anotherswitching element 24 and theoutput inductor 25. Asmoothing capacitor 26 is coupled between theoutput terminal 22 and theground 27. Instead of the switchingelement 24, a diode in which the forward direction is a direction from theground 27 to theoutput inductor 25 may be used. The DC-DC converter including theswitching elements - In the current path A1 from the
input terminal 21 to theoutput terminal 22, thefrequency filter 30 is coupled in series to the current path on theswitching element 23 side with respect to the connection point of thesmoothing capacitor 26. Thefrequency filter 30 is a band-stop filter in which the operating frequency band of theantenna element 50 is a stop band.FIG. 1 illustrates an example in which thefrequency filter 30 is inserted in the current path A1 between theswitching element 23 and theoutput inductor 25. - When the
switching element 23 and theother switching element 24 are alternately turned on and off, the DC voltage inputted to theinput terminal 21 is stepped down and outputted from theoutput terminal 22. -
FIG. 2A is an equivalent circuit diagram illustrating an example of thefrequency filter 30. A ferrite bead (F.B.) can be used as thefrequency filter 30.FIG. 2B is an equivalent circuit diagram illustrating another example of thefrequency filter 30. An LC parallel resonant circuit can be used as thefrequency filter 30. The LC parallel resonant circuit reflects a part of the signal in the frequency range near the resonant frequency. The ferrite bead attenuates the signal of a frequency in the stop band by converting the signal into heat. In the case in which the influence of the reflected wave cannot be ignored, it is preferable to use a ferrite bead as thefrequency filter 30. - Next, an excellent effect obtained by using the configuration of the wireless communication module according to the first embodiment will be described.
- When the switching
elements output terminal 22 to thetransceiver circuit 41, and thus, a noise filter such as a ferrite bead is inserted usually between theoutput terminal 22 and thetransceiver circuit 41. - According to the study conducted by the inventors of the present application, it has been found that, in addition to noise leaking from the
output terminal 22 to the outside, noise flowing into theground 27 through the smoothingcapacitor 26 and the stray capacitance of the substrate may be transmitted to theantenna element 50, and as a result, wireless communication may be inhibited. In particular, when theantenna element 50 shares the ground with thepower supply circuit 20, theantenna element 50 is easily affected by noise flowing into theground 27 of thepower supply circuit 20. - In the first embodiment, the ringing noise caused due to switching of the switching
elements frequency filter 30, and as a result, it is possible to reduce the noise flowing into theground 27 through the smoothingcapacitor 26. Accordingly, it is possible to suppress deterioration of quality of communication using theantenna element 50. The stop band of thefrequency filter 30 can be set to the operating frequency band of theantenna element 50. When theantenna element 50 operates in the 2.4 GHz band, the stop band of thefrequency filter 30 may be set to the 2.4 GHz band; when theantenna element 50 operates in the 5 GHz band, the stop band of thefrequency filter 30 may be set to the 5 GHz band. - Next, with reference to the drawings of
FIGS. 3 to 5 , the result of the evaluation experiment performed to observe the noise suppressing effect in the wireless communication module according to the first embodiment will be described. - The noise coupled to the
antenna element 50 during WiFi search is measured in the state in which the transceiver circuit 41 (FIG. 1 ) is disconnected from a feed point 51 (FIG. 1 ) of theantenna element 50 and thepower supply circuit 20 operates in a shield box. The evaluation experiment was conducted with respect to three kinds of configurations: a configuration in which thefrequency filter 30 is not inserted, a configuration in which a 15 nH inductor is used as thefrequency filter 30, and a configuration in which a ferrite bead is used as thefrequency filter 30. Theantenna element 50 used was one that operates in the 2.4 GHz band. -
FIG. 3 is a graph illustrating the transmission characteristic S21 of each of the inductor and the ferrite bead used in the evaluation experiment. The horizontal axis represents the frequency in the unit of “MHz” and the vertical axis represents the transmission characteristic S21 in the unit of “dB”. The transmission characteristic S21 indicated inFIG. 3 is measured by using a measurement system of a 50 n characteristic impedance. The solid line and the dashed line in the graph ofFIG. 3 respectively indicate the transmission characteristics S21 of the ferrite bead and the inductor. As the inductor, one with a resonance point at 6 GHz, which is determined in accordance with inductance and stray capacitance, was used. As the ferrite bead, one with the 2.4 GHz stop band was used. -
FIG. 4 is a graph illustrating spectrums of noise coupled to the antenna element 50 (FIG. 1 ). The horizontal axis represents the frequency in the unit of “MHz” and the vertical axis represents the noise level in the unit of “dBm”. The square symbols in the graph ofFIG. 4 indicate noise levels in the case in which the frequency filter 30 (FIG. 1 ) is not inserted. The triangle symbol and the dashed line indicate noise levels in the case in which an inductor is used as thefrequency filter 30. The circle symbols and the solid line indicate noise levels in the case in which a ferrite bead is used as thefrequency filter 30. The high noise level appearing near the frequency of 2455 MHz is caused by signals for WiFi search. The thin solid line illustrated in the graph ofFIG. 4 indicates the noise floor. -
FIG. 5 is a bar graph illustrating noise levels at frequencies of 2444 MHz, 2446 MHz, and 2448 MHz extracted from the noise level spectrums illustrated inFIG. 4 . The vertical axis inFIG. 5 represents the noise level relative to the noise floor. - As seen in
FIGS. 4 and 5 , when a ferrite bead is used as thefrequency filter 30, the noise level is lower than that in the case in which thefrequency filter 30 is not inserted and in the case in which an inductor is used as thefrequency filter 30. - According to the evaluation experiment described above, it was confirmed that it is possible to reduce the noise coupled to the
antenna element 50 by using thefrequency filter 30 in which the stop band is the operating frequency band of theantenna element 50. - Next, the
wireless communication module 10 according to a second embodiment will be described with reference toFIG. 6 . Hereinafter, description of the configuration common to the wireless communication module according to the first embodiment will be omitted. -
FIG. 6 is an equivalent circuit diagram of thewireless communication module 10 according to the second embodiment. In the first embodiment, thefrequency filter 30 is inserted in the current path on the output side with respect to the switchingelement 23; and on the input side, the switchingelement 23 is directly coupled to thebypass capacitor 40. In the second embodiment, afrequency filter 31 on the input side is coupled in series between thebypass capacitor 40 and the switching element 23 (between thebypass capacitor 40 and the input terminal 21). Thefrequency filter 31 on the input side has the same filter characteristic as that of thefrequency filter 30 on the output side. - Next, an excellent effect obtained by connecting the
frequency filter 31 on the input side will be described. When the switchingelement 23 is switched on and off, noise is generated also on theinput terminal 21 side due to the equivalent series inductance (ESL) and the like of thebypass capacitor 40. Also, noise is generated by switching the switchingelement 24. In the wireless communication module according to the second embodiment, thefrequency filter 31 is inserted also on theinput terminal 21 side, and as a result, it is possible to inhibit the propagation of noise generated on theinput terminal 21 side and transferred to theantenna element 50 via thebypass capacitor 40 and theground 27. - Next, a modified example of the second embodiment will be described. In the second embodiment, the
frequency filter 30 is inserted on the output side with respect to the switchingelement 23 and theother frequency filter 31 is inserted on the input side. In this modified example, thefrequency filter 30 on the output side is removed and thefrequency filter 31 is coupled only on the input side. As such, a frequency filter may be inserted in series in at least either the current path between the switchingelement 23 and the smoothingcapacitor 26 or the current path between the switchingelement 23 and thebypass capacitor 40. By inserting a frequency filter on at least one side, noise coupled to theantenna element 50 via theground 27 can be reduced. - Next, the
wireless communication module 10 according to a third embodiment will be described with reference toFIG. 7 . Hereinafter, description of the configuration common to the wireless communication module (FIG. 6 ) according to the second embodiment will be omitted. -
FIG. 7 is an equivalent circuit diagram of thewireless communication module 10 according to the third embodiment. Thewireless communication module 10 according to the second embodiment has the oneantenna element 50. Thewireless communication module 10 according to the third embodiment includes, in addition to theantenna element 50, anantenna element 55 that operates in another frequency band. For example, the oneantenna element 50 operates in the 2.4 GHz band and theother antenna element 55 operates in the 5 GHz band. Thetransceiver circuit 41 transmits and receives signals in two frequency bands. Thetransceiver circuit 41 includes a baseband circuit and a high frequency circuit (RF circuit), in which the baseband circuit and the high frequency circuit are both coupled to a duplexer (separator). - In addition to the
frequency filter 30, anotherfrequency filter 32 is coupled in series in the current path between the switchingelement 23 and the smoothingcapacitor 26. The stop bands of the frequency filters 30 and 32 are the respective operating frequency bands of theantenna elements frequency filter 31, anotherfrequency filter 33 is coupled in series in the current path between the switchingelement 23 and thebypass capacitor 40. The stop bands of the frequency filters 31 and 33 are the respective operating frequency bands of theantenna elements - Next, an excellent effect obtained by using the configuration of the
wireless communication module 10 according to the third embodiment will be described. Thewireless communication module 10 according to the third embodiment can perform wireless communication in two frequency bands. Furthermore, in the two frequency bands, it is possible to reduce the noise flowing into theantenna elements ground 27. - Next, a wireless communication module according to a fourth embodiment will be described with reference to
FIGS. 8A and 8B . Hereinafter, description of the configuration common to the wireless communication module (FIG. 1 ) according to the first embodiment will be omitted. -
FIG. 8A is an equivalent circuit diagram of thewireless communication module 10 according to the fourth embodiment. In thewireless communication module 10 according to the fourth embodiment, a switchingcircuit 71 forming a part of the power supply circuit 20 (FIG. 1 ) and aWiFi module 70 including thetransceiver circuit 41 are used. Thepower supply circuit 20 includes the switchingcircuit 71 included in theWiFi module 70, theexternal output inductor 25, and the smoothingcapacitor 26. Thefrequency filter 30 is coupled in series between the switchingcircuit 71 and theoutput inductor 25. - An external power supply terminal of the
WiFi module 70 serves as theinput terminal 21 of thepower supply circuit 20. Thebypass capacitor 40 is coupled between theinput terminal 21 and theground 27. The DC voltage outputted from theoutput terminal 22 of thepower supply circuit 20 is inputted to theWiFi module 70. -
FIG. 8B is an equivalent circuit diagram of thewireless communication module 10 according to a modified example of the fourth embodiment. In this modified example, theWiFi module 70 not including thepower supply circuit 20 is used. The switchingcircuit 71, theoutput inductor 25, and the smoothingcapacitor 26 of thepower supply circuit 20 are externally coupled outside theWiFi module 70. The DC voltage applied to the external power supply terminal of theWiFi module 70 is applied to theinput terminal 21 of the externalpower supply circuit 20. Also in this modified example, thefrequency filter 30 is coupled in series between the switchingcircuit 71 and theoutput inductor 25. - As illustrated in
FIGS. 8A and 8B , thefrequency filter 30 can be externally coupled to theWiFi module 70 together with theoutput inductor 25 and the smoothingcapacitor 26. By externally coupling thefrequency filter 30, it is possible to suppress deterioration of wireless communication quality due to the noise flowing into theground 27, similarly to the case of the first embodiment. - The embodiments described above are mere examples, and as might be expected, the configurations described in the different embodiments may be partially replaced or combined with each other. In particular, almost identical effects and advantages achieved by almost identical configurations of the embodiments are not mentioned in every embodiment. Furthermore, the present disclosure is not limited to the embodiments described above. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.
Claims (16)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2018-084784 | 2018-04-26 | ||
JPJP2018-084784 | 2018-04-26 | ||
JP2018084784 | 2018-04-26 | ||
PCT/JP2019/015150 WO2019208173A1 (en) | 2018-04-26 | 2019-04-05 | Wireless communication module |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2019/015150 Continuation WO2019208173A1 (en) | 2018-04-26 | 2019-04-05 | Wireless communication module |
Publications (2)
Publication Number | Publication Date |
---|---|
US20210036409A1 true US20210036409A1 (en) | 2021-02-04 |
US11601055B2 US11601055B2 (en) | 2023-03-07 |
Family
ID=68294093
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/072,667 Active 2039-07-17 US11601055B2 (en) | 2018-04-26 | 2020-10-16 | Wireless communication module |
Country Status (4)
Country | Link |
---|---|
US (1) | US11601055B2 (en) |
JP (1) | JP6798642B2 (en) |
CN (1) | CN112042130B (en) |
WO (1) | WO2019208173A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11050448B2 (en) * | 2017-11-30 | 2021-06-29 | Murata Manufacturing Co., Ltd. | Wireless communication device |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090279456A1 (en) * | 2008-05-08 | 2009-11-12 | Lee Jun Goo | Cascade-type multiplex radio communication relay system |
US20100194475A1 (en) * | 2007-12-17 | 2010-08-05 | Motoyuki Okayama | Amplifying circuit with bypass circuit, and electronic device using the same |
US20130154868A1 (en) * | 2011-12-14 | 2013-06-20 | Infineon Technologies Ag | System and Method for an RF Receiver |
US20160006476A1 (en) * | 2014-07-01 | 2016-01-07 | Sofant Technologies Ltd. | Wireless communications apparatus |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4013751B2 (en) * | 2002-12-05 | 2007-11-28 | 富士電機ホールディングス株式会社 | DC-DC converter |
JP2004364394A (en) * | 2003-06-04 | 2004-12-24 | Canon Electronics Inc | Power control method for electronic apparatus, power control program for electronic apparatus, and electronic apparatus |
CN100559319C (en) * | 2003-09-16 | 2009-11-11 | 诺基亚有限公司 | Be used in the hybrid switched mode/linear power amplifier power supply in the polar transmitter |
CN201274535Y (en) * | 2008-08-19 | 2009-07-15 | 深圳市同洲电子股份有限公司 | Power supply circuit of mobile television and mobile terminal |
TWI360940B (en) * | 2008-09-12 | 2012-03-21 | Realtek Semiconductor Corp | Voltage converting apparatus |
TWI390833B (en) * | 2009-12-31 | 2013-03-21 | Delta Electronics Inc | Multi-output dc-to-dc conversion apparatus with voltage-stabilizing function |
WO2017163481A1 (en) * | 2016-03-23 | 2017-09-28 | 三菱電機株式会社 | Dc-dc converter |
-
2019
- 2019-04-05 CN CN201980027271.7A patent/CN112042130B/en active Active
- 2019-04-05 WO PCT/JP2019/015150 patent/WO2019208173A1/en active Application Filing
- 2019-04-05 JP JP2020516185A patent/JP6798642B2/en active Active
-
2020
- 2020-10-16 US US17/072,667 patent/US11601055B2/en active Active
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100194475A1 (en) * | 2007-12-17 | 2010-08-05 | Motoyuki Okayama | Amplifying circuit with bypass circuit, and electronic device using the same |
US20090279456A1 (en) * | 2008-05-08 | 2009-11-12 | Lee Jun Goo | Cascade-type multiplex radio communication relay system |
US20130154868A1 (en) * | 2011-12-14 | 2013-06-20 | Infineon Technologies Ag | System and Method for an RF Receiver |
US20160006476A1 (en) * | 2014-07-01 | 2016-01-07 | Sofant Technologies Ltd. | Wireless communications apparatus |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11050448B2 (en) * | 2017-11-30 | 2021-06-29 | Murata Manufacturing Co., Ltd. | Wireless communication device |
Also Published As
Publication number | Publication date |
---|---|
JPWO2019208173A1 (en) | 2020-12-17 |
CN112042130B (en) | 2021-10-01 |
JP6798642B2 (en) | 2020-12-09 |
CN112042130A (en) | 2020-12-04 |
WO2019208173A1 (en) | 2019-10-31 |
US11601055B2 (en) | 2023-03-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10116348B2 (en) | High-frequency power amplifying module and communication apparatus | |
US9281853B2 (en) | Integrated circuit for communication | |
JP5237414B2 (en) | Terminal apparatus for simultaneously transmitting signals to which different wireless communication schemes are applied through a plurality of frequency bands | |
US7245883B2 (en) | Radio communication apparatus, radio communication method, antenna apparatus and first duplexer | |
CN106559048B (en) | Multimode radio frequency power amplifier | |
US10277287B2 (en) | Antenna system and harmonic suppression element | |
CN110474657B (en) | High-frequency transceiving switch integrated circuit and method thereof | |
US9136915B2 (en) | Wireless communication device | |
CN108847866B (en) | Radio frequency front end adjacent channel interference suppression circuit and WLAN access equipment | |
US11855677B2 (en) | High-frequency signal transmission-reception circuit | |
US11996869B2 (en) | Radio frequency module and communication device | |
US11601055B2 (en) | Wireless communication module | |
KR101325196B1 (en) | Receiver using impedance shaping | |
Ikonen et al. | Multi-feed RF front-ends and cellular antennas for next generation smartphones | |
US11258422B2 (en) | Communication module | |
EP3772184A1 (en) | A tunable matching network for a transceiver | |
JP6525055B2 (en) | Power supply circuit | |
KR101262343B1 (en) | Radio frequency transmitter-receiver | |
CN106170925B (en) | High-frequency front-end circuit | |
CN111492588A (en) | Wireless communication device | |
CN219041744U (en) | Amplifying circuit, wireless communication module and electronic device | |
KR101752898B1 (en) | The user equipment for transmitting simultaneously signals applied two seperate wireless communication scheme through a plurality of frequency band | |
Zhao et al. | A Coupled Resonator Decoupling Network for in-device coexistence of two collocated antennas | |
EP3202010B1 (en) | Combined rf charging and communication module and methods of use | |
KR20230135136A (en) | Multi-band power amplifier circuit and radio frequency transceiver |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: MURATA MANUFACTURING CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:OHNO, AKIHIRO;ISHIWATA, YU;SIGNING DATES FROM 20200904 TO 20201008;REEL/FRAME:054080/0060 |
|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: APPLICATION DISPATCHED FROM PREEXAM, NOT YET DOCKETED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: FINAL REJECTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE AFTER FINAL ACTION FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |